Head Mounted Displays

VR Helmets: the dinosaurs

Oculus DK2 Lens – Characteristics


The Oculus DK2 is a remarkable VR headset, producing a remarkably wide field of view with very inexpensive single element optics. VRtifacts was curious about the characteristics of the Oculus DK2 lens: what size, what material, and what focal length? The lenses themselves have quite a bit of chromatic aberration, giving the impression that they are very low cost simple lenses. The diameter is 41mm and focal length (of the “B” lens) is approximately 45mm.

Distortion and Chromatic Aberration

This is a fairly high degree of magnification which produces significant distortion and chromatic aberration (color fringing near the lens periphery.) Oculus takes full advantage of modern day graphics cards using OpenGL to pre-distort opposite to the lens distortion, and to individually distort the red, green, and blue channels to (imperfectly) correct for chromatic aberration. The color fringing correction is imperfect because the lens bends different frequency light by different amounts. The process in the lens is a continuous curve across the color spectrum, while the graphics card only corrects at 3 discrete frequencies corresponding to red, green, and blue… essentially a step function. However, since the display emits moderately narrow bands red, green and blue, we perceive good chromatic aberration correction.

AMOLEDs (DK2 uses a Samsung Galaxy Note 3 Full HD Super AMOLED) use organic electroluminescent materials which do not emit single frequency red, green, and blue colors. Instead they emit a range of light frequencies consisting of a spectral curve for each color primary. AMOLED spectral curves are narrower than produced by IPS LCDs (used in Apple retina displays), but the width of the frequency range for each primary is not a single frequency. The Oculus chromatic aberration correction technique only works perfectly at the exact center frequencies of each (RGB) emission curve. Since the AMOLED emissions spread around these ideal Oculus corrected center frequencies, chromatic fringing can not be totally eliminated by the Oculus technique.


Spectrum plot for Apple iPhone 4 and 5 vs. Samsung AMOLED (older version than Note 3)


Why Sell Out? Oculus -> Facebook

A lot of people are fuming over today’s announcement that Facebook would be buying Palmer Luckey’s Oculus. Palmer and company produced two mainstream marketed development kit head mounted displays which became darlings of the grassroots VR/Gamer community. Starting with Kickstarter, Oculus, channeled through Palmer’s and later John Carmack’s charisma and a hacker friendly attitude, built a loyal and vocal user base, one that championed the ethos of open source and quasi-community development.

Tonight, there’s a lot of disappointment and vitrol that Oculus has abandoned the community, and worse yet (from their perspective), sold out to the Devil incarnate. How could Palmer, who just announced the deal on Reddit, have turned his back on the admiring crowds? Who would have thought the Oculus enthusiasts could be turned into a howling mob in the course of a single afternoon?

Were they betrayed? And by who?

It’s easy to forget that Oculus funding didn’t end with Kickstarter. There’s the Venture Capitalists. Unlike the Kickstarter money-for-prototype funding, the VCs were getting equity, board seats, and a preferential position in the decision making process. VCs don’t take major stakes unless they receive major control of their target.

So when Oculus was offered $400m in cash plus $1.6B in Facebook stock (plus another $300m incentive bonus), was Palmer really making that call alone? After multiple VC funding rounds and stock incentives to key employees, Palmer must have relatively small minority stake in Oculus, although even so the deal involves a considerable sum for him. But a minority share and non-preferred stock means that his vote is in no way decisive… the Venture Capitalists, led by Andreessen Horowitz, make the big time financial decisions. They invest based on their strategic relationships with potential buyers like Facebook (Andreessen sits on the board of Facebook… no small thing.)

It’s only natural that the VCs would push hard for the deal. Inasmuch as Oculus never really had a strategy to rake in 9 figure profits cash on the barrel at huge multiples of their original investment, what’s an investor to do? Let’s hypothetically (and generously) say that there would have been a 50% chance that Oculus could generate $2B in profits (or other liquid value) within the next 4 years. If the investors were to allow Oculus to remain independent they’d be giving up a certain $2B right now, in exchange for a potential payout down the road. How big would that payout need to be? Well…, in this make-believe scenario the investors are essentially deferring their $2B as a high risk loan. They should then receive interest payments on their loan (the time value of money.) But when you risk other-peoples’-money you must pay the vig. Let’s assume 20% per year (that’s low… I promise!) So… discounting for the 50% risk and the vig, the VCs need more than $5B in profit on the future bet. That significantly decreases their (50%) chance of success.

Time to take the money and run!

Does that make Palmer Luckey the bad guy? No, it just makes him the guy who took the VC money without realizing that control had also been surrendered. This is a dance that occurs with every venture capital deal; the term sheets have the control clauses permanently etched.

Is the Facebook deal a bad thing? Good thing? Oculus developed technically well conceived and implemented head mounted displays. The VR displays are/were wildly popular with a community of up to 75,000, doubtless enhanced by the ultra-low $300 price tag. They would need to sell tens of millions of units at this price point in order to realize anything like the $2B Facebook offer. Realistically, the price point needed to be double (or triple) in order to have margins comparable to normal consumer electronic gear. I don’t see them achieving millions of units sold at $600-$900/unit. Pundits have suggested other unspecified, service based, revenue streams. Lacking the clout of a Facebook/Google sized borg, I don’t feel like they could ever reach a critical mass capable of bringing in $5B+ in value (other than equity.)

While the Facebook ethic is the nightmare scenario for the highly independent Oculus community, their alternatives were limited. VCs always rely on the profitability of equity not of product. What will FB do with Oculus? Unknown. But if the Oculus product never makes a single cent, it nonetheless will not die an ugly and horrible cash flow strangulation death; what would certainly have been their fate absent being made part of the borg.


W-Industries Unscripted

W-Industries (Virtuality) always seemed to have a PR person riding herd on any video material that was released about the company or products. Everything the public saw was tightly scripted and edited.  But… here’s a 1992 video from inside the factory that’s more of a home movie cum operations tutorial. We are guided through some of the guts of the Series 1000, the pre-play systems, and the assembly area.

Don’t forget to turn on the YouTube subtitles, the audio track is in Swedish.

Virtual Reality (1991) – “Many Believe It Will Revolutionize The Way We Live”

ABC Primetime covers the VR scene in Sept. 1991. Although this news report conflates computer animation footage with Virtual Reality, it also features interviews with Jon Waldern, Fred Brooks, Howard Rheingold, Mike McGreevey, and C L Dodgson (virtually, of course.) With the advantage of hindsight, it’s interesting to see which predictions from 23 years ago have panned out and which are way out in left field.

… and from the where-are-they-now club, we get a brief glimpse of video footage from Symbolics Inc. (remember LISP?), a hot up-and-comer in computer graphics back in the day.

Vintage VR-4 Head Mounted Display Teardown

Here’s a much more detailed tear down of the Virtual Research VR-4 Head Mounted Display, done by one of the engineers at VR sometime in 1994. He shows us how to remove the back light inverter and the main PCB.

‘Scuse the vintage VHS EP mode recording. I was trying to save on video tape costs; a 6 hour tape cost $1.50!

Digital VR Rehab

For years, therapists would attempt to treat smokers and alcoholics using real-life triggers. Let addicts see a lighter or an empty bottle, or even a photo of something smoking or drinking related, to trigger cravings, then teach them coping strategies. It was limited because patients could tell they were in a lab and their new found coping skills were not always transferrable to the real world. Enter Virtual Reality:

The theory being that the immersive VR world better approximates the real world, allowing better skills transference and allowing researchers to easily AB test different scenarios. A pilot program at Duke run by assistant professor Zach Rosenthal with funding from the National Institute on Drug Abuse and the Department of Defense has already run about 90 people through this VR rehab trial. No formal conclusions have been reached, but preliminary data suggests effectiveness. More reading here.

Awesome VR Optics for 1″ Class Displays At Less Than Ten Dollars!

Professional wide field of view Virtual Reality optics for less than the price of a couple of double lattes! A while back I demonstrated a design for Leep On The Cheap, a proof of concept for wide field of view optics on 3″ to 4″ display panels. Trouble was… there was quite a bit of distortion and chromatic aberration. However, it sparked quite a bit of thought and development in the VR DIY community. They’re the ones doing all the heavy lifting.

32mm Erfle Eyepiece

32mm Erfle Eyepiece

So… it’s time to come back with another optical design for wide field of view VR, but this time the optical qualities are first rate and remarkably inexpensive. Of course there are a new set of trade-offs: field of view is limited to about 65 deg. (not bad, but not totally immersive), and I rely on somewhat smaller display panels, about 1″ to 1.5″ diagonal. This is roughly the same as the: Nvision Datavisor LCD, Visette Pro, and Virtual Research VR4/V6/V8.

This design, and many commercial versions, rely a the unique characteristic of telescope eyepieces: that they can be directly used as HMD optics without modification. Even better, they’re made in fairly large quantity, with a large selection of optical characteristics and quality, and somebody else has already solved the issues of distortion, chromatic aberration, internal reflections, coatings, and aspheric design. Did I mention that they’re inexpensive. The sweet spot are either Erfle or Plossl designs; Erfle offers wider field of view. Even wider fields can be achieved with variations on the Nagler design, but the weight becomes prohibitively high.

It’s easier to give the tour by video… viddy this my droogies:

Lens sources:

30mm fl Erfle from Surplus Shed – $9.50

32mm fl Erfle from Surplus Shed – $12.50

I’ll leave you hanging re: the LCD panel. The one in the video shown above was torn from a Virtual Research V6; low res, old school.

More info on eyepieces:


Common Telescope Eyepiece Designs